If you’re daydreaming about buying a home or need to lower the payment on the one you already have, you might pay a visit to the Quicken Loans mortgage calculator. You’ll be asked a quick succession of questions that reveal how much cash you have on hand or how much your home is worth and how close you are to paying it off. Then Quicken will tell you how much you’d owe per month if you got a loan from them and asks for your name, email address, and phone number.

You might fill in the contact form, but then have second thoughts. Do you really want to tell this company how much you’re worth or how in debt you are? You change your mind and close the page before clicking the Submit button and agreeing to Quicken’s privacy policy.

But it’s too late. Your email address and phone number have already been sent to a server at “murdoog.com,” which is owned by NaviStone, a company that advertises its ability to unmask anonymous website visitors and figure out their home addresses. NaviStone’s code on Quicken’s site invisibly grabbed each piece of your information as you filled it out, before you could hit the “Submit” button.